Understanding Dynamic Processes at Nanoscale Working Interfaces for Solar Energy Conversion

Introduction

To slow down global warming and to overcome the reliance on fossil fuels, a transition to a carbon neutral society fueled by renewable energy sources will be crucial. Therefore, the conversion of solar energy to storable, energy-dense fuels will be an important step to satisfy the need for clean and reliable power.

Importance of Solar-to-Chemical Conversion

Economically viable systems for solar-to-chemical conversion often base on thin film photoelectrodes with highly complex internal architectures. The combination of different length scales of fundamental physical processes and inherent film heterogeneities results in a complex micro- and nanoscale behavior, which often controls critical processes of the macroscale device.

Challenges in Characterization

The typical macroscale characterization of material properties conceals important insights into:

• Structural heterogeneity
• Compositional heterogeneity
• Optoelectronic heterogeneity at the nanoscale
• Local photoelectrochemical reaction processes
• Material stability

Research Program Overview

To provide a comprehensive portrait of the elementary steps associated with light-to-chemical energy conversion at their natural length scales and under working conditions, DynNano will launch a multimodal research program. This program will leverage a complementary suite of emerging nanoscale techniques for in-situ and operando characterization of energy materials.

Focus on Transition Metal Oxynitride Semiconductors

The approach will be applied to novel transition metal oxynitride semiconductors, which are poised to overcome efficiency and stability limitations of pure oxides and pure nitrides. By thoroughly correlating their nanoscale and macroscale properties, DynNano will establish the link between nanoscale processes and macroscopic performance of photoelectrochemical systems.

Goals and Outcomes

With the gained understanding, DynNano aims at closing the photoelectrochemical cycle at the nanoscale using precisely microstructured photoelectrodes for standalone water splitting. Overall, DynNano will provide the knowledge basis for the rational development of efficient, stable, and scalable solar fuel devices.